FIGS. 1 to 3 illustrate a known cleaner head 1 for a vacuum cleaner. The base of the cleaner head 1 comprises a suction inlet 2, a front plate 3 located forward of the suction inlet 2, and a rear plate 4 located rearward of the suction inlet 2. Each of the two plates 3,4 is inclined or ramped relative to the horizontal. When the cleaner head 1 is placed onto a carpeted surface, the two plates 3,4 penetrate the piles of the carpet. As a result, the air that is drawn into the suction inlet 2, which passes beneath each of the plates 3,4, penetrates more deeply into the carpet. When the cleaner head 1 is pushed forwards, the ramped surface of the front plate 3 helps to flatten the piles of the carpet. As a result, the front plate 3 moves relatively smoothly over the piles of the carpet. The rear plate 4, on the other hand, presents a vertical surface to the piles and therefore tends to dig into the piles. As a result, a greater push force is required in order to manoeuvre the cleaner head 1 forwards. Moreover, as the cleaner head 1 is pushed forwards, the cleaner head 1 may skip over the carpet as the rear plate 4 first digs into the piles and then, with sufficient push force, jumps clear of the piles. Skipping of the cleaner head 1 is likely to worsen the cleaning performance since the cleaner head 1 is momentarily lifted from the carpet. The same behaviour is observed when the cleaner head 1 is pulled rearwards.